Recording with the piezoelectric microphones in class

The perils of recording with contact mics

Day two of recording sounds. Thank goodness I demonstrated making a contact mic to each small group. In two days, about eight microphones have broken! Fortunately, I have a group of backup mics to pass out to my classes! I would not have predicted this, even though the mics are relatively fragile.




Mostly this is due to over-enthusiastic taping of the piezo element onto the object being recorded.

Students seems to be getting the hang of using the various flavors of Audacity to record. They have even improved upon my workflow suggestions!

Originally, I suggested that they record a short sound (10-20 seconds), then export it immediately as an aiff or wav.

Instead, some students made multiple recordings in the same workspace, then muted all tracks save the single sound being exported. Much more efficient!

The next step will be learning to edit and modify the samples into usable loops. This includes learning how to properly apply metatags with the Apple Loops Utility as well as sequencing in GarageBand.

Because GarageBand is proprietary, it is difficult for students without Macs to work at home. I plan to touch on open-source alternatives in the near future.

On my YouTube Channel, I have been posting similar examples of this kind of workflow with my "cat dance" series of experiments using a Korg Monotron.

The Monotron is a wonderful analog ribbon synthesizer that is about the size of a wallet. I record improvisations into the computer, chop up some samples, then make short electronic music sketches.

Here are some examples:



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Recording Sounds

Today, we hooked up our piezo mics to all kinds of instruments and objects including Indonesian frog-callers, toy accordion, bajo, cajon, toy piano, kalimba, and sleigh bells.

Before turning them loose, I demonstrated the recording process.  As a "light at the end of the tunnel", I created a modified loop and played it in GarageBand.

First, I showed them how to tape the microphone wire onto the side of the instrument to relieve stress on the small lead wires and solder joints.

After plugging into the computer, I demonstrated how to set the proper sample size, bit rate, and file types in the preferences pane.  As a reference, we recorded as AIFF, 44,100, and 16-bit. I did this to facilitate assembling projects in GarageBand.

I checked the input levels with a sample recording, then recorded about 10 seconds of improv.  I did a quick edit, counted off eight beats, then applied some effects.  I added a wet phaser and reversed the clip.  I exported the loop into the Apple Loops Utility, added metatags on the transients, and exported that into GarageBand.

Because of the metatags, I could now manipulate the loop in GarageBand.  I demonstrated how to sync it with other pre-fab loops and create a simple piece.  This whole process took me about 7 minutes. The remainder of the time was spent with the students working in groups to build a small library of recorded sounds from which they will learn to create loops, and eventually, compose a piece.

I should mention that I teach them to use Audacity so we have an open-source-cross-platform tool students can use at home, either for homework, or hopefully, their own projects.  In the absence of one-to-one, this helps level out the technological playing field.

Next week, we will continue collecting sounds, before I teach them how to edit and place metatags into the files.










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Tutorial Video on Piezoelectric microphones for posterity

Today I finished making a tutorial video about contact microphone construction.  Besides the explanation of how to make a microphone, I tried to convey the idea that once you capture signal, you are only limited by your imagination in how you use it.

I made a little electronic-improvisation in Ableton using a few loops and a number of audio effects on our video clip.  First, I matched the sound, as captured by the Sony recorder in the video, to the video from the point-and-shoot.  I then loaded the clip into Ableton and did a brief sketch with four samples of the video.

Finishing mics and researching unusual contact mic uses

Period one has finished mic construction and testing. While period one, group three built, the other students researched unique artistic uses for contact mics online.

I am curious to read their posts to see if anything unusual surfaces. I hope they dig deep. Even with slightly esoteric subjects like this, I am increasingly finding many answers coming from link farms or other content scrapers.

It is frustrating, and, it shows that students need to keep critical distance from online sources until they can be properly vetted.

It also shows the need to search deep into Google for relevant information. I will do a bit if experimenting with some other search engines to see how the results stack up. My gut tells me Google will still probably be best, and, it will be interesting to see if this holds true.

Wondering aloud, I wonder if there are Yahoo or Google communities around this particular topic?

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Wrapping up mic construction

I've got quite a collection of mics that I've been making as I demonstrate. I think this weekend, I'll make some sample recordings and a tutorial vid for the next step.

Students not making mics have been researching and blogging about the Hornbostel-Sachs classification of instruments. Hopefully, considering instruments by how they create sound will inspire some unusual electroacoustic creations as we move towards sonifying the trees.

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Piezo mics

Mics wound and bagged, ready to record! I think my kids have enjoyed making them. I hope they feel the satisfaction of having made something with their hands.

The trick will be to use the mics as tools of creativity!

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Piezo contact microphone construction

Today is the second of what I project to be three days of contact mic construction.

First, I demonstrated how to make a microphone for the whole class.  I took special care to point out pitfalls and how to avoid injury.  Then, I brought students by their workgroups to a small table where i walked them through the process.

Students strip microphone cable, twist the copper, and solder it to piezo discs. We test them on our Sony handheld recorder, plugging them into the mic jack and tapping them to see if we get signal.

While small groups construct mics, the rest of the class continues to research and blog about their mythical trees. They are looking for inspiration in myth, art, and poetry as they plan to sonify a real tree.

The microphone construction is slow. It is difficult to strip and twist such small wires. I have also inhaled way too much vaporized solder as students operate the iron for the first time. About 65% of all the students have finished their contact mics.




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The seed is planted!

Today, the Electroacoustic Tree project comes online.  We are all creating blogs to document the process.  Links to all of the blogs will be hosted on this project homepage.

The idea is to sonify the trees in the courtyard.  By using computers, piezoelectric microphones, amps, and speaker arrays, we will turn the trees into musical sound sculptures.

To date, my classes have been split into small workgroups, researched different trees in myth, art, and science, selected trees, and are researching interesting ideas about their trees.

Tomorrow, we will learn how to build contact microphones out of piezo elements.  While portions of the class work on construction, others will be learning or refining their computer DAW skills.

Stay tuned!